Baseline dental examinations were conducted in September 1969 on approximately 1000 first- and second-grade school children in Wayne County, North Carolina. Children assigned to one test group chew an acidulted phosphate-fluoride (APF) tablet containing 1 mg. F., rinse for 30 seconds with the resulting solution and then swallow the material. Another test group follows the same procedure but, in addition, they repeat the procedure at least 3 hours later with another APF tablet, also containing 1 mg. F. A third group use a placebo tablet and serves as a control. The treatments are carried out each day in school under supervision of the classroom teacher. Treatments will continue until the respective participants have completed grades six and seven. Follow-up evaluations of the caries preventive effects of the proceduses were conducted in April 1972, after 30 months of study, and in May 1974, after 55 monts of study. The 55-months examinations also included an assessment for signs of dental fluorosis. A report of the 30-month findings has been published in the July 1974 JADA. A brief report of the 55-month findings was presented at the 1975 AADR meeting and a detailed manuscript of these findings is being prepared for publication. The next follow-up examinations for dental caries are scheduled for September 1975.